This invention relates to a steering column arrangement.
DE 197 00 175 A1 discloses a steering column arrangement which comprises a steering spindle mounted in a casing tube so as to be rotationally movable. A switch module is fixed radially and axially on the casing tube at that end of the steering spindle which protrudes into the vehicle interior. As a result, the switch module is held immovable with regard to the steering spindle. For this purpose, the switch module is supported on a bearing which is arranged on the steering spindle.
The switch module is secured axially on the casing tube via a bayonet closure, while the radial fixing is effected via a clip which surrounds the casing tube.
The mounting of the switch module thus requires two steps, and even small tolerance deviations of the components can make it impossible to connect contacts of electronic components which are integrated in the switch module, such as a steering angle sensor, correctly to the steering wheel.
It is an object of the invention to provide a steering column arrangement which simplifies the mounting of a switch module and ensures reliable connection of the switch module to the steering wheel.
According to the invention, the object is achieved by a steering column arrangement that includes a steering spindle mounted in a casing tube so as to be rotationally movable, and a switch module which is held immovably with respect to the rotational movement of the steering spindle and is fixed radially and axially on the casing tube. The switch module is supported on a bearing which is arranged on the steering spindle, and comprises a centering device which, under a force which is oriented coaxially with respect to the longitudinal axis of the steering spindle, fixes the switch module on the casing tube and clamps it radially.
The steering column arrangement comprises a steering spindle which is mounted in a casing tube so as to be rotationally movable and a switch module which is held immovably with respect to the steering spindle and is fastened to the casing tube. According to the invention, the switch module is equipped with a centering device and a bearing, and is supported on the steering spindle via the bearing. The action of a force which is oriented coaxially with respect to the longitudinal axis of the steering spindle on the centering device makes it possible for the switch module to be moved during mounting in the axial position as far as an end position, such that it is oriented radially automatically in the process. Here, it is of advantage that only one step, the application of a coaxially acting force, is sufficient to fasten the switch module to the casing tube. At the same time, the switch module is pulled to the steering wheel by the application of the axial force, so that there can be no axial movement between the switch module and the steering wheel. In addition, it is possible to virtually preclude rotation or tilting of the switch module, so that the steering angle sensor which is integrated, for example, in the switch module is thus mounted in a faultfree manner.
In one refinement, the centering device comprises a stator and clamping jaws which interact during application of the axial force, in such a way that the switch module is centered automatically on the casing tube.
The stator can be connected to the bearing in order to support the switch module on the steering spindle, such that the switch module is held immovably during rotation of the steering wheel.
For uniform introduction of the axially acting force to the clamping jaws, the stator can be connected to each clamping jaw via a spring element in one preferred embodiment.
As each clamping jaw is pulled fixedly to the casing tube by way of a support, the switch module can be secured axially on the casing tube under the action of the axial force.
That face of the clamping jaw which faces the stator advantageously extends obliquely with regard to the longitudinal axis of the steering spindle, so that the stator which is moved in the opposite direction to the clamping jaw brings the clamping jaw into contact with the casing tube.
This effect can be reinforced if the inner face of the stator extends parallel to the oblique face of the clamping jaw.
An elevation which protrudes from that face of the clamping jaw which faces the casing tube can be pressed to a more or less pronounced extent into the casing tube during mounting, as a function of the force which is acting on it, ensuring reliable holding of the switch module on the casing tube.
The axial force can advantageously be applied by means of a steering wheel bolt. This has the advantage that, using a method step which is necessary in any case (the fixing of the steering wheel to the steering spindle), the switch module can be fixed at the same time.
A leaf spring which engages in a cut-out of the casing tube is provided on the stator as a radial securing means of the switch module, which radial securing means can at the same time serve during mounting as a captive securing means.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.